With the advent of broadcast television, movie producers realized they needed more than live television programming. By turning to film-originated material, they would have access to the wealth of films made for the cinema in addition to recorded television programming on film that could be broadcasted over the airwaves at different times. Moving picture video is typically recorded or encoded at a pre-determined frame rate. For example, cinema films are typically recorded at a fixed rate of 24 frames per second (fps). Video as broadcast for television in accordance with the NTSC standard, on the other hand, is encoded at 30 fps. Video broadcast in accordance with European PAL or SECAM standards is encoded at 25 fps. However, the difference in frame rates between film generally (24 frames/s) and for television (30 or 25 frames/s) meant that simply playing a film onto a television camera would result in flickering when the film frame was changed in mid-field of the TV frame.
In recent decades, telecine which is primarily a film-to-videotape process, as opposed to film-to-air is employed. The most complex part of telecine is the synchronization of the mechanical film motion and the electronic video signal. Every time the video part of the telecine samples the light electronically, the film part of the telecine must have a frame in perfect registration and ready to photograph. This is relatively easy when the film is photographed at the same frame rate as the video camera will sample, but when this is not true, a sophisticated procedure is required to change frame rate.
Conversion between frame rates has created challenges. One common technique of converting frame rates involves dropping or repeating frames within a frame sequence. For example, a 3:2 pull down is used to convert 24 fps motion picture video to 30 fps or 60 fields per second. Each first frame spans 3 video fields, while each other second frame spans two fields. For instance, a cycle that starts with film frame B yields a 3:2 pattern: B-B-B-C-C-D-D-D-A-A or 3-2-3-2 or simply 3-2. In other words, there is no difference between the 2-3 and 3-2 patterns.
In video, the cadence pattern or telecine information is identified and detected Telecine information is useful for identifying system issues during media processing such as editing, transcoding and so on. It is important to correctly identify the cadence pattern in video even in case of noise, freeze frames, slow motion and complicated video sequences.
Existing methods for identification of cadence pattern and analysis are capable of detecting only one particular type of cadence pattern in the video. When the pattern sequences are complex or large there is every possibility of incorrect patterns or sequence being captured. In addition, there are no means to cross check such errors in identification of the sequence. In addition, most of the methods employed today are prone to noise, slow motion and have difficulty in eliminating freeze frames. Further, these methods are cumbersome in nature. Some of the methods may also require the system to be trained initially as a result making the overall process time consuming.
Due to the above stated reasons there is a need for generic algorithm to be able to detect any kind of cadence pattern in the video including complex sequences without errors. Further, the method must be efficient and free from initial training requirements.